Attorneys challenging a death sentence before the state's highest court last week dug deeply into online historical documents to divine the intention behind what they think is a never-before-interpreted part of the state's constitution.

Public defender Brian Saccenti and a team of lawyers rested their argument in part on a once-famous 18th-century book by a young Italian nobleman named Cesare Beccaria, who suggested that capital punishment should be reserved for treasonous criminals.

Charles Carroll of Carrollton, who helped draft the Maryland Constitution, wrote to a friend that he approved of Beccaria's "Just & Judicious observations," Saccenti's team wrote in a brief. Carroll was also a signer of the Declaration of Independence.

And a version of Beccaria's argument appears in the state's Declaration of Rights in an often-overlooked clause which reads "That sanguinary Laws ought to be avoided as far as it is consistent with the safety of the State."

Saccenti rolled out the argument on Thursday before the Court of Appeals on behalf of Jody Lee Miles, who was convicted of a 1997 Wicomico County murder.

Imposing sanguinary laws — that is, the death penalty — on murderers is illegal, Saccenti said, because people like Miles do not threaten the stability of the state if they are imprisoned.

Saccenti said in an interview that appeals against capital punishment since the 1960s have tended to focus on the federal Constitution. He began to poke around in obscure parts of Maryland's founding documents in search of new approaches.

Striking on the sanguinary laws wording, which Saccenti said is unique to Maryland, his team turned to Google Books and other historical databases to see what it meant to 18th-century Americans and bolster their case.

"We were looking for as many occasions when this phrase was used," he said, adding that without the online sources, "I have no idea how you'd do this research."

The unusual approach to fashioning an appeal was slow going, Saccenti said, occupying the time of three or four people for most of a year.

Not to be outdone, the attorney general's office, which handles appeals in criminal cases, did some historical research of its own.

Senior counsel James E. Williams noted that William Paca, an early governor of the state who also helped draft the constitution, was apparently not squeamish about executions: He signed six death warrants.

Baltimore Archbishop William E. Lori asked the governor to push a death penalty repeal in the legislative session that starts in January, offering his support in a letter that was hand delivered to the state house this morning.